Self-priming impeller pump for gas and fluid mixtures



NOVVSO, 1937. A Q STRATTQN 2,100,365

SELF PRIMING IMPELLER PUMP FOR GAS AND FLUID MIXTURES Filed May 18, 1931 5 Sheets-Sheet 1 lc. s2 25 0 FIG. la. w

FIG. /"c.

Q o FIG/b.

9 o Q o 7 E a o if, 53 j o I 40 A 'fl 4z 43 so A ,32 v \l r u a 4/ 2/ M 8 -43 L 20 INVEIVT OR ALBERT c. STRATTON ATTORNEY Ndv. 30, 1937. A. c. STRATTON SELF PRIMING IMPELLER PUMP FOR GAS AND FLUID MIXTURES s Sheets-Sheet 2' Filed May 18, 1931 FIG. 2a.

FIG. 3

- INVENTOP ALBERT C. $TRA77UN l ATTORNEY Nov. 30, 1937. A. c. STRATTON 2,100,365

' SELF PRIMING IMPELLER PUM P FOR GAS AND FLUID MIXTURES Filed May 18, 1931 5 Sheets-Sheet s a 4 I (76.511

IN VEN TOR A T TORNEV Y Pat nted ov. so. 1931 1,100,365

UNITED STATES. PATENT OFFICE s ar-rams nurnunn rum FOB ens AND FLUID mx'rmns Albert C. Stratton, Lincoln Park, N. 1., minorto Alfred 'S. Marlow, Ridgcwood, N. J.

Application May 18, 1931, Serial No. 538,129

14 Claims. (01. 103-113) This invention relates to impeller pumps for the pump. The suction system is connected to gas and fluid mixtures and more particularly to this priming connection and includes a. trap pumps'of this kind which are self-priming. valve.

' In accordance with known arrangements for The control means preferably comprises a adapting a pump of this type for self-priming a short restricted passage in the priming connec- 6 reservoir for priming water is placed above the tion dimensioned according to requirements and pump; a connection is made for supplying the located above the level of the pump axis. A reservoir from the discharge side of the-pump movable member is arranged to automatically and another connection serves to discharge the. open and close the restricted passage under the i0 reserve water to the suction side of the pump; influence of the main flow in the suction system, 10 automatic means are provided for controlling and may also serve to deflect or disperse the the how of reserve water; means are also prostream of priming water emanating from the vided for separating air from the reserve water restricted passage. Loss of priming water may at the discharge side of the pump and means are be prevented by means such as a trap valve reprovided for mixing of reserve water and air ferred to above or by a pocket formation in the 15 described, which under ordinary operating contion of the construction and operation of certain at the suction side of the pump during priming suction system. I operation. These and other features in different modifi- An object of this invention is to provide a selfcations, and their coordinate functions, will be priming pumping arrangement of the kind just better understood, from the following descripditions will handle gas and fluid mixtures of preferred embodiments of the inventionillus: widely varying gas content with high efficiency trated in the attached drawings. and without continued loss of prime, thus elim- Referring to the drawings: .inating the most common cause of trouble, which Figs. 1a, b, and 0 show a self-priming may be ascribed to accumulation of air in the pumping system in accordance with one embodisuctlon lines. 1 ment of the invention; Fig. 1a being a side view Another object is to enable such a pumping partly in section showing the system under norarrangement to quickly resume normal pumping mal pumping operations; Fig. 1b being a detailed operation when, after a failure'thereoflthe main" view corresponding to'a portion of Fig. 1a. showwater supply has been replenished. ing the relation of certain parts under priming A principal object is the ability of the pumping conditions; and Fig. 10 being an end view partly system to develop a high degree of suction or in section taken on line ic-lc of Fig. 1a; vacuum in the suction system. Figs. 2a. and b showa modification of the Among other objects of the invention are automatic control arrangement shown in Fig. 5 ability of the pumping arrangementto: handle 1a; Fig. 2a showing the parts under normal muddy and gritty water with little tendency to pumping operation; and Fig. 2b showing these clog; ability to operate effectively at freezing parts under priming conditions;

temperatures; ruggedness and. compactness of Fig. 3 shows another modification of the conconstruction and simplicity of moving parts. 'trol arrangement shown in Fig. 1a:

40 Forthe attainment of these and other objects Figs. 4a and b show another embodiment of 40 the following features of the invention 'may be the invention in which all free-moving mechaniincorporated in" a pumping arrangement such as cal parts have been, eliminated from the priming that referred to above. system; these figures showing. the parts under The invention in its preferred form is' applied 1 normal and priming conditions, respectively;

to a centrifugal pump of any conventional form. Figs. 5a and b show a modification of the em- 45 v The reservoir, or tank, for priming water is bodiment shown in Figs. 4a and b; Fig. "5a showy 4 'placed above the pump and connected directly ing certain parts under normal operating conto its discharge opening; the discharge or overditions; and Fig. 5b showing these parts under flow connection from the system is connected priming conditions.

at the top of the tank. Screens, baille plates or Referring now to the outfit illustrated in Figs.

other means for aiding the separation of air and A la, b and c, a centrifugal pump 20 of anyhconsolids from the priming water may be located ventional type has the intake side of its stawithin the tank. From the lower portion of the tionary housing extended in any convenient mantank'a short priming connection of large crossher into aconnector piece forming a tubular 5:6v sectional area is made to the suction opening of intake channel II, which may be connected through a suction pipe or hose or other convenient means'22, to the main water supply, the

level of which may be as much as 28 feet below the center line AA of the outfit. The discharge opening 23 of the pump connects to an outlet 24 through a tank 30, which is effective as a. reservoir for recirculation water. The discharge circuit is completed through a direct passage such as tube 60 to an overflow or to a discharge pipe or other convenient means 25 connected to outlet 24 at the top of the tank for disposal of the discharge water.

unrestricted passage through tank 30 and has openings or perforations for feeding reserve water.

to the tank. The discharge water may be spilled over at the level at which the discharge pipe is shown or may connect to a head, the height of which, of course, is limited by the pressure which can be developed by the pump.

20 A recirculation path for the pump is completed from the discharge opening 23 through perfora-,

tions in tube 60, tank 30, and priming connection 3| forming a wide well opening into the tank The tube 60 forms a direct at its upper end and connecting at its lower end i 26 through a short restricted passage or spout 32 to the intake channel 2| at a point immediately in front of the suction opening of the pump. A hinged member 40, located in the intake channel, carries a disc 4|, which serves to open and close the lower opening of the spout 32, and a vane 42, which projects into the main fiow through the intake channel 21. Vane 42 is of a size such that ample space is left around its edge to permit of free passage of the intake water- 35 in any position of the vane. A flap valve 50 is arranged to shut off the intake passage 2| from the suction pipe 22 for trapping the water in the main flow during priming and to prevent loss of priming water during priming or when the out- 0 fit is shut down for a short time. As a further precaution the intake chamber 2| may be provided with an S connection 26 for the suction pipe to form a pocket with a water level about even with "the pump axis A-A. The tube 60 forms a direct unrestricted passage through tank 30 to outlet 24 and is preferably placed at a small angle with the direction of the discharge flow from discharge opening 23. Openings 5i,

52 and 53, which are normally closed, are provided at convenient places for cleaning of the system and refilling of tank and pump.

The pump 20 comprises the usual stationary volute or housing, which may be supported by brackets 10 of any convenient design, and a plurality of impeller blades (not shown) .which ro tate within the volute, being driven through shaft H by any convenient power supply, such as a gasoline motor. With the pump running at normal speed, the main flow of water will be 0 pumped through pipe 22, valve 50, and 'past the vane 42, which due to the velocity of the water will be held in the position shown in Fig. 1a to force the disc II to closethe spout 32; the water of solid matter which will not interfere with the operation of the priming equipment. Such air as may enter the tank from the tube will again be able to escape through the upper perforations of the tube into the discharge pipe 25. It has been found that the separation of air from the water in the tank may be aided by placing the tube 60 at an angle as shown in Fig. 1c. The main discharge flow will thus be slightly deflected and thereby cause the reserve water to rotate within the tank to effect acentrifugal separation of Water and air.

When the rate of flow of intake water through the intake passage 28 is reduced, the pressure on the vane 42 causes the disc 41 to fall away from the spout 32 partly by gravity and partly under the pressure of the reserve Water in tank 30, thereby admitting a stream of reserve water to the suction side of the pump and thus compensating at least in part for the reduction 'in the main fiow. The pump may thus continue its functioning and will be replenishing the reserve water in the tank through the screen 60.

'When the main supply fails altogether the suction pipe 22 will be filled with air, the disc ll will be fully open to admit the maximum volume r v of reserve water, which, however, in nearly all cases will be insufficient to maintain the prime in the pump. Valve 50 will be closed to prevent loss-of reserve water but will admit air freely to the pump. As soon as enough reserve water has collected in the pump to prime it, it will develop suction in the pipe 22 until the reserve water has been expelled from the pump, when the prime will again break. This cycle will be con-;

tinually repeated until such time when the water in the main supply has risen enough to cover the foot of pipe 22. After this the drinking time begins, that is, the pump will raise the water a,

able outfits for excavation work, are frequently used under circumstances which make continuous and efiicient operation difficult. It may, for example, be operated on suction lifts as great as 28 feet, and whereas the pump may be loaded to full capacity whenthe water supply is ample, a leaky suction pipe may seriously reduce the load or break the prime; the water supply may at times be insufficient to continuously keep the pump fed. On well point jobs a plurality of pipes may be drivenv into a sand and gravel bed and connected together by a main pipe leading to the suction side of the pump; even though the lift may be small, a great resistance to the flow.

through the sand must be overcome by a high vacuum from the pump, and much air may be taken in by one or more of the points. Under such circumstances great difficulties have been experienced in the past with pumps of the centrifugal type in attempting to secure reliable selfpriming operation, especially where a vacuum as high as 26 to 27inches may be required in the suction system. It is essential that a practical outfit, even at great suction depth, have a short drinking time, i. e., quickly fills the suction system and resumes normal operations to avoid dan-,

2,1oo,sos 3 ger of flood due to an excessive rise of the water' about the suction pipe.

In a practical outfit, built in accordance with the invention, it is furthermore essential that 5 trapping and recirculation of air be prevented; it 'i s also necessary that the outfit be capable of being fully drained to prevent freezing during idle periods. The arrangement shown in Figs. in. b and c is 'particularlyadapted to meet these exigencies, as will appear from the following more detailed discussion of its functioning. I

The automatic control means comprising spout 32, vane 42 and disc 4|, being placed on the suction side of the pump are responsive to the main is flow in the intake. This has many advantages over arrangements in which the control of the flow'of reserve water into the suction side is controlled from the discharge side of the pump.

Thus a single unitary device is obtained by com-- '25 water rather than by a pressure condition set up in the discharge system and is thus independent of the varying heads which the pump may be 7 working against and operates in a more positive manner; the vane 42 being placed in the flow in 80 the suction side rather than in the discharge side,

9 its operation is not affected by the flow of discharge water, and since the loss of water manifests itself sooner on the suction side than on the discharge side, the time of response of the as vane is advanced by this arrangement and reserve water may be supplied even before the pump loses its prime; the absence of long narrow connections between pump and tank greatly aids the quick response of reserve water to sud- 40 den changes in the position of the vane.

There are, however, other very essential features involved in the present arrangement which attach to its functioning in the presence of air in the main flow. In general, conditions in the 45 intake passage 2| are such that air would separate from the water and pass in the upper zone of this passage; solids will tend to pass in the lower zone; the control element 42, being located in the upper zone, will not obstruct the passage of the solids or become clogged by them; the

position of the vane will be directly determined by the water level in passage 2|. Under steady conditions, as in case of a leak in pipe 22, the

separated flow of air and wateir through passage 55 2| will be fairly uniform and the vane will admit 'a fairly uniform flow of, reserve water, the adjustment of parts being such that the prime of the pump will be-maintaine d. As more or less air passes, more or less reservewater will be ad- .0 mitted', so that the energy lost in maintaining the recirculation of reserve water is'kept as low under the different conditions as is possible without the chance of the pump losing its prime. The uncertainty of pressure conditions in the dis- .5 charge side due to the great variations in pump pressure, when air passes through the pump, has little effect upon the control of the reserve water, due to the relatively small orifice in spout32 and also due to the small leverage of the action of 10 the reserve now on disc 4| as compared with. the

large leverage of the main flow acting on vane 42. The control means is also utilized as a means for mixing air and water into a fairly uniform mixture, and its location immediately in front of the 75 suction'opening of the pump is of great imporby the placing of the spout 32 in or immediately above the air zone in passage 2|, since the stream of reserve water is thereby forced to pass through 10 the air zone and to contact and mix with the air. The co tact is increased by deflection against disc 4| and; consequent spraying of the reserve water into the air zone, and considerable quantities of air are thus carried along into the pump. When the disc 4 moves far away from the spout 32 as in the case when the main flow is greatly reduced or fails altogether, the bar 43 in the hinged'member 40 will be in the path of the reserve stream, which becomes partly deflected as a spray into the air zone, and partly split into two streams contacting doubly with the air and being projected into the pool of water in the bottom of passage 2|, thereby setting up a violent turbulence in the pool and thus forcing the air into the water; the air capacity of the pump is thereby greatly increased.

The automatic control means thus correlate the function of varying the supply of reserve water to keep the pump primed and maintain high efllciency with the function of varying the capability of the pump to suck air, both in accordance with variations in the main wat r flow.

The vacuum, which the pump will develop, will, of course, be affected by the amount of air mixed in with the water passing through the pump, but 3 aside from this the suction in the suction system is greatly affected by the flow of reserve water into the suction side of the pump; as more reserve water is admitted, as by increasing the orifice of spout 32, less water will be sucked up through pipe 49 22. Considering the conditions prevailing during a priming operation, aheavy flow of reserve water would absorb large quantities of air and thus tend to shorten the drinking time, i. e., the time for priming the system after the main supply has been replenished; however, since a heavy flow of reserve water would limit the vacuum, the suction lift on which the pumpcan operate is limited correspondingly and consequently is determined by the orifice in spout 32. This relation is, how- 50 ever, of particular importance where a high vacuum is required to overcome a resistance to the suction flow as in well point jobs. As explained above, the lift in this case may be small'but' the flow through sand and gravel surrounding the well 5. point is greatly impeded and at times considerable'quantities of air enter with the water. Thus high vacuum is essential to secure sufficient water capacity and must be coupled with a decided capability to handle air. For this purpose .the orifice of spout 32 must'be limited to admit sufficient reserve water for'mixing with air but oi insuflicient volume tosatisi'y to an appreciable extent the vacuum developed by the pump.

v It has been found that for average operating 05 conditions for a portable outfit of the usual sizes. the most s factory operation is secured by making the area of the orifice of spout 32 approximately one sixth of the area of the discharge opening of the pump; thus for three inch. four inch and six inch pumps, the spout orifices should be one and one quarter inch, one and five eighths inches and two and one half inches in diameter, respectively; however; for special conditions these 1 dimensions may be varied considerable; thus a 15 four inch pump has been found to work in accordance with special requirements with a one and one eighth inch or a two inch orifice. 7

Under any particular operating conditions the most desired functioning may readily be observed and attained by varying the area. of orifice 32, as by inserting bushings 33 (see Fig. 1a) of diiferent sizes in the orifice and thereby varying the ratio of reserve flow to main suction flow.

The efliciency, as well as the successful priming operation, of a pumping system, of the present kind, depends to a large extent upon the expulsion of air from the recirculation water. 'To this end a straight and substantially vertical discharge path through the reservoir 30 is formed by the tube 60, and the tube is provided with alarge number of perforations so that the reserve water passes slowly and evenly into the tank; in this manner air bubblesmay readily escape through the discharge opening 24 and they are largely prevented from entering the tank. The centrifugal action in tank 63 due tothe slight angle of tube 60 results in air bubbles gathering in the quiet area in the center of the tank, moving to the top and escaping again through the upper'perforationsof tube 60. The well 3| is placed near the periphery of the tank where the rotating water contains least air and the flow through the well, being in a. downward direction and very slow clue to the large cross-sectional area of the well, further safeguards against air in appreciable amounts passing through spout 32 with the recirculating water.

In regard to prevention of clogging by sand or other solids, the arrangement just described is very efl'ective. Like the air contained in' the water, solids will tend to pass directly to the discharge pipe through tube 60, the direction and velocity of the water remaining practically unchanged in this path. The low velocity of reserve water passing through the perforations into the tank will allow only fine particles to enter the tank, where they will be kept traveling along the peripheryand thus be prevented from lodging in the center of the tank. a The particles will tend to flow down through the well, where they may readily be washed out through the: spout 32 by the reserve water.

Since no connections carrying water are ofsmaller size than the suction and discharge connections, the system has no weak points at which freezing would be especially likely to occur. No

- pockets exist which cannot be drained through the valve 53 at the bottom of the pump housing, which also eliminates a danger of freezing.

.In accordance with the modification shown in Figs. 2a and b of the system shown in Figs. 1a, b and c, the intake channel 2I comprises a ball valve chamber, containing a ball I22, having alower seat I23 forthe ball opening to the suction pipe "and having an upper seat I24 forming part of spout 32 leading from the well 3|. Suitable guides I25, of any convenient design, are arranged within the chamber for keeping the ball aligned with the seats I23 and I24. The ball I22 is substantially spherical and is made of suitable material, such as an outer shell of vulcanized rub- Under priming conditions the ball settles on the lower seat I23 and permits free recirculation of water from the tank 30 to maintain the prime of the pump, at the same time as it prevents" loss of recirculating water into the suction pipe 22.

Under conditions when the intake flow carries a substantial proportion of air, the ball will take an intermediate position between the two seats'I23 and I24 determined; by the proportion of air to water in the main fiow, thereby admitting sufllcient water from the tank 30 to maintain the prime.-

In this modification, as in the embodiment shown in Fig. 1a, the control of recirculating water is effected by the proportion of air to water in the main flow. An air zone is provided in the intake chamber around the spout 32, and the recirculating water emitted from thespout will be deflected, and spread into the air zone by the surface of the ball I22, thereby securing a thorough mixing ofair and water at the entrance to the pump and consequently insuring a. high vacuum.

The-arrangement shown in Fig. 3 is a modification of the embodiment illustrated in Fig. 1a and is characterized by additional means for controlling the flow of reserve water into the intake chamber 2|, which means comprises a diaphragm controlled operating device 2I0 affected by the back pressure in the discharge system to control the position of the hinged member .40 in conjunction with the control exerted on that member by the main flow.

This modification is particularly adapted for operation of the pump against a considerable head and the purpose of the'device 2I0 is principally to permit an adjustment pressure to, be applied to the hingedmember 40 in such a way that a large back pressure acting thereon through the spout 32 may be substantially neutralized.

The device 2I0 comprises a diaphragm 2II mounted in a housing 2I2 having openings 2I3 for admitting the water and pressure from tank 33 to the upper side of the diaphragm. The lower part of the housing 2I2 is connected to a tubular member 2I4 which extends through the bottom portion of the well 3| into the intake chamber 2i, so that the pressure, at any time existing in that chamber, may be directly communicated to the lower side of the diaphragm 2. A rod 2I5 is connected to the center-of the diaphragm and passes through suitable guiding means 2I6 at the lower end of tube 2, where it terminates in a flattened portion 2 I I. The rod 2 I 5 engages an extension 2I8 on the hinged member 40 at a point where the downward pressure, transmitted through the rod from the diaphragm 2, will counteract the pressure exerted from the tank on the member 40 through the spout 32. A spring 220 is mounted in the upper portion of housing of the pump connects through the intake passage 32I and an intake opening 322, in the bottom of .tank 30, to a tubular riser 323, placed within the tank 30 and in turn connecting through the top of the tank 30 to the suction system 22. The

riser 323 has an upper portion 324, which carries a flexible annular operating member 325, and a lower portion 326, the upper edge of which forms a seat for the flexible member 325. The member 325 may be of rubber or other suitable material and may be stiflened by metal. valve (not shown) of any type should be included inthe suction system.

The normal flow through the pump is as fol- 1ows:-From the main supply through intake system'22, riser 323, intake channel 32l, pump 20, tubular passage of filter 60, and discharge system 25. Under normal operating conditions, when ample water is taken in, the passing of water through the riser 323 causes the flexible member 325 to seat tightly against the portion 325, thereby shutting off the reserve'flow. Under priming conditions, or when the proportion of water in the main flow is very small, the pressure on the upper side of flexible member 325 is lowered, causing the member 325 to assume its natural position, such as shown in Fig. 4b, or, dependent upon the rate of water taken in, to assume some intermediate position, thereby admitting water from the tank through the space between flexible member 325 and the seat of 326 into the intake passage 32!.

In the present embodiment. the reserve water,

:entering underthe flexible member 325, is ejected into a region of the intake system which is passed by any air that may be contained in the main flow and which is located well above the center line.A-A of the pump. Intimate mixing of air and water and consequent high suction is thus insured by the ejection of reserve water into the passing air, as well as by the turbulence in the pool which always lodges below the line A-Ain the intake passage 32l. Also by this .arrangement the reserve water is controlled by 40 the proportion of air to water in the main flow reaching-in a downward direction towards the intake channel 32l and'has an upper flared portion 423, which is clamped between-rings 430 and 43l to the upper portion 424 of the riser 423. The upper edge of the lower portion 426 of the riser 423 forms a seat for the flared portion oi flexible member 425. The ring 43l is provided with one or more passages 432 for admission of reserve water from the tank 30 to the seat on lower portion 425. The tubular portion 421 of flexible member425 may be stiflened by a metal tube 429 or by other suitable means.

Under normal operating conditions a heavy flow of water will cause the flexible member 425 to take a position such as shownin Fig. 5a and "thereby to substantially shut ofi the flow of reserve water. When the flow of water is reduced or altogether jails, the flexible member will change its shape, as shown in Fig. 5b, partly due to the pressure on the outside of the tubular portion 421 by the water in tank 30 and partly due to the reduced pressure or vacuum in the riser 423.

In this figure the discharge opening 23 is shown A trap to lead directly into tank 30, A shield 450 sure rounds the riser 423 and is provided with perforations 46l near the bottom of tank 30, there'- by preventing coarse particles from entering the passages 432 and interfering with the automatic control of the reserve water. This arrangement may, of course, be replaced by the tubular screen shown in Fig. 1a., and it may replace the tubular screen in any of the other embodiments del scribedabove, depending upon the constituency of the pumping medium in any particular case.

l. A pumping system for pumping varying mixtures of air and water which comprises a centrifugal pump having a suction opening, a suction connection for the main water flow into said opening, a recirculation path for said pump of negligible impedance and efiective as a reservoir for priming water, a short restricted passage forming the junction between said path and said suction connection and presenting substantially the total impedance to flow in said path, and a shutter member for said passage having a plurality of surfaces for impact with the reserve flow through said passage and fastened to extend into the air zone within said suction connection for operation by varying impact with the main flow through said suction connection to shut off the reserve flow through said passage.

2. A pumping system comprising a centrifugal an impeller chamber, a suction line leading into said impeller chamber; an impeller in said chamber, a container for priming fluid associated with said chamber, a port leading from said container to said impeller chamber, a discharge passage leading from said impeller chamber, a valve for controlling said port to admit priming fluid to said impeller chamber when open and to substantially exclude priming fluid therefrom when closed, and means for holding said valve open to admit priming fluid to said impeller chamber until the air is, substantially exhausted from the suction line and until a fluid flow with a selected velocity head is established therein and thereafter closing said valve and maintaining it closed while this condition continues to exist, said last named means comprising a baflle member of less area than the cross-section of the suction line projecting into the path of flow of the fluid therein but moveable substantially out of said path of flow by the action thereon of said selected velocity head of fluid.

4'. A pumping system comprising a centrifugal pump having discharge and suction openings, a tank for reserve water connected directly be tween said openings, forming substantially the total of a recirculation path for said pump, a suction connection communicating with said suction opening, automatic control means comdifferently shaped body portions for deflecting the flow of reserve water from said passage in different manners in accordance with theratio of air to water in the main suction flow.

5. A pumping system for continuous-pumping of air and water in varying mixtures without loss of prime which comprises a centrifugal pump having discharge and suction openings, a tank for reserve water directly connected to said discharge opening, a main suction connection for said suction opening, an aperture interconnecting directly said tank and said connection at a point close to the suction opening and forming a valve seat, a shutter member for control of reservewater through said aperture including a surface for seating onto said valve seatagainst the force of flow of reserve water and including another surface for varying engagement the reserve and main flows upon said shutter member to provide approximate optimum conditions of high vacuum at high capacity operation and of short drinking time at low capacity operation for a given effective suction lift for the pump.

6. A pumping system for operation on varying mixtures of air and water comprising a centrifugal pump having a suction opening, a reaervoir for priming water adapted to be refilled from the discharge of said pump, a suction connection forisaid opening for the main flow of air and water, an aperture interconnecting said reservoir and suction connection and formingua valve seat, and a hinged shutter member for seating onto said .valve seat for control of the flow of reserve water, said ishutter member having a vane contacting at varying angles with the main-flow in accordance with the ratio of air to water thereof and having different deflecting portionsof diflering configurations contacting with the flow of reserve water at the various angles of said vane to vary the deflection of the reserve flow by said shutter member in accord-' ance with the ratio of air to water in the main flow and thereby varying the relation between opening directly into said suction connection above the level of the center of said pump and an automatic shutter for said outlet placed within said suction connection, said automatic shutter comprising a ball-shaped body portion arranged for control of said outlet and to be directly op- 5 erated upon by the main flow in said suction connection. Y

8. A pumping system for co inuous pumping of air-and water, separately a (1 mixed, without loss of prime which comprises a centrifugal l0 pur 'n'p having a suction opening and a discharge opening, a main suction connection for said suctioii opening, a tank for reserve water connected to said discharge opening, a path from said tank joining said suction connection immediately in 16 front of said suction opening, a valve chamber at the point of juncture of said path and connection having a valve seat for each of said path and connection, respectively, a shutter within said chamber adapted to ply between and seat 20 onto said two seats, said shutter being under control of the forces of the opposing streams acting thereupon from said path and connection to control the proportion of reserve water to water in the main flow, and said shutter having 25 substantially spherical seating areas adapted to serve also as diffusing surfaces for spraying of the two streams into the segregated airin said chamber, and means within said chamber for guiding said shutter past said suction opening.

9. A self-priming pumping system for pumping air and water in varying proportions comprising a centrifugal pump having suction and discharge openings, a water reservoir directly interconnecting said openings for quick supply- 3 ing of reserve 'water in response to reduction ofthe main water flow, valving means for automatically varying the passage of water between said reservoir and said suction opening under the varying force of the main water flow into 40 said suction opening,'said valving means comprising an' annular valve seat and an annular shutter member therefor, said member having a central opening for the passage of the main water flow into said suction opening.

- 10. A pumping system for pumping air and shutter member therefor to control the flow from said reserve water connection to said suction opening, said shutter member having a central opening for continuous passage of the flow from 55 said suction connection and having a surface subject to impact with the flow from said sucation connection for movement-of said member relative to said seat in accordance with the ratio of water to air in said suction flow 11. A pumping system comprising a centrifugal pump, a suction connection for the main water flow, a recirculation path for said pump including a,reservoir, control means for recirculation water from said reservoir, said control means comprisinga restricted outlet from said path opening directly into said suction connection above the devel of thecenter of said pump and an automatic, shutter for said outlet placed within said suction connection, s'aid automatic shut- 70 ter-comprising a flexible collar adaptedto pass thefmain flow through its central opening.

12. A pumping system comprising a\ cen-a. trifu'gal pump, a suction connection for the main water flow, a recirculation path for said pump ll including a reservoir, control means for recirculation water from said reservoir, said control means comprising a. restricted outlet from said path opening directly into said suction connection above the level of the center of said pump and an automatic shutter for said outlet placed within said suction connection, said automatic shutter comprising a flexible collar having a substantially tubular expansible portion and said outlet comprising a substantially annularxopening in said suction connection.

13. A pumping system for continuous pumping of air and water in any proportion comprising a centrifugal pump, a suction connection,

a discharge connection, a water reservoir having curved contour and placed above said pump and directly interconnecting said connections,- a strainer arranged within said reservoir to prostantially vertically upwards from said pump into said discharge connection and to provide a subthe discharge flow from said pump to produce by said subdivided flow a centrifugal action within said reservoir for segregation of air to escape through said discharge connection, and an automatic valve at the bottom of said reservoir for varying ejection of reserve water substantially freed of air directly into said suction connection,

in accordance with varying proportions of air in the main flow through said suction connection.

14. A pumping system comprising a centrifugal pump, a suction connection for the main water flow, a recirculation path for said pump including a reservoir, control means for recirculation water from said reservoir, said control means comprising a restricted outlet from said path opening directly into said suction connection above the level of the center of said pump and an automatic shutter for said outlet placed within said suction connection, and further comprising a discharge connection for said pump, a dim'atic shutter for at least. partial compensation for the eflective head pressure on said shutter. V ALBERT C. STRATI'ON. 

